diff --git a/examples/example.rs b/examples/example.rs
index c383000..99f965e 100644
--- a/examples/example.rs
+++ b/examples/example.rs
@@ -4,12 +4,12 @@ use std::result::Result;
 
 use chainerror::*;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func3() -> Result<(), Box<Error + Send + Sync>> {
+fn func3() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
     Ok(())
diff --git a/examples/tutorial1.rs b/examples/tutorial1.rs
index d296a92..4ac1eb3 100644
--- a/examples/tutorial1.rs
+++ b/examples/tutorial1.rs
@@ -2,25 +2,25 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(_) = do_some_io() {
         Err("func2 error")?;
     }
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(_) = func2() {
         Err("func1 error")?;
     }
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     func1()
 }
diff --git a/examples/tutorial10.rs b/examples/tutorial10.rs
index 15eae31..cf13909 100644
--- a/examples/tutorial10.rs
+++ b/examples/tutorial10.rs
@@ -3,14 +3,14 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
 derive_str_cherr!(Func2Error);
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     Ok(())
@@ -39,7 +39,7 @@ fn func1() -> ChainResult<(), Func1ErrorKind> {
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         match e.kind() {
             Func1ErrorKind::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
diff --git a/examples/tutorial11.rs b/examples/tutorial11.rs
index 00e3d74..5f85c23 100644
--- a/examples/tutorial11.rs
+++ b/examples/tutorial11.rs
@@ -3,14 +3,14 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
 derive_str_cherr!(Func2Error);
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     Ok(())
@@ -45,7 +45,7 @@ fn func1() -> ChainResult<(), Func1ErrorKind> {
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         match e.kind() {
             Func1ErrorKind::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
diff --git a/examples/tutorial12.rs b/examples/tutorial12.rs
index 8cdc8aa..f5e38de 100644
--- a/examples/tutorial12.rs
+++ b/examples/tutorial12.rs
@@ -3,14 +3,14 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
 derive_str_cherr!(Func2Error);
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     Ok(())
@@ -54,7 +54,7 @@ fn handle_func1errorkind(e: &Func1ErrorKind) {
     }
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         match *e {
             Func1ErrorKind::Func2 => eprintln!("Main Error Report: func1 error calling func2"),
diff --git a/examples/tutorial13.rs b/examples/tutorial13.rs
index 78dee31..c345157 100644
--- a/examples/tutorial13.rs
+++ b/examples/tutorial13.rs
@@ -2,14 +2,14 @@ pub mod mycrate {
     use chainerror::*;
     use std::io;
 
-    fn do_some_io() -> std::result::Result<(), Box<std::error::Error + Send + Sync>> {
+    fn do_some_io() -> std::result::Result<(), Box<dyn std::error::Error + Send + Sync>> {
         Err(io::Error::from(io::ErrorKind::NotFound))?;
         Ok(())
     }
 
     derive_str_cherr!(Func2Error);
 
-    fn func2() -> std::result::Result<(), Box<std::error::Error + Send + Sync>> {
+    fn func2() -> std::result::Result<(), Box<dyn std::error::Error + Send + Sync>> {
         let filename = "foo.txt";
         do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
         Ok(())
@@ -42,7 +42,7 @@ pub mod mycrate {
     }
 }
 
-fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     use mycrate::func1;
     use mycrate::ErrorKind;
     use std::error::Error;
@@ -57,7 +57,7 @@ fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
         }
 
         eprintln!();
-        let mut s: &Error = &e;
+        let mut s: &dyn Error = &e;
         while let Some(c) = s.source() {
             if let Some(ioerror) = c.downcast_ref::<io::Error>() {
                 eprintln!("caused by: std::io::Error: {}", ioerror);
diff --git a/examples/tutorial14.rs b/examples/tutorial14.rs
index e73d747..84c3491 100644
--- a/examples/tutorial14.rs
+++ b/examples/tutorial14.rs
@@ -182,7 +182,7 @@ pub mod mycrate {
     }
 }
 
-fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     use mycrate::func1;
     use mycrate::ErrorKind;
     use std::error::Error;
@@ -197,7 +197,7 @@ fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
         }
 
         eprintln!();
-        let mut s: &Error = &e;
+        let mut s: &dyn Error = &e;
         while let Some(c) = s.source() {
             if let Some(ioerror) = c.downcast_ref::<io::Error>() {
                 eprintln!("caused by: std::io::Error: {}", ioerror);
diff --git a/examples/tutorial15.rs b/examples/tutorial15.rs
index c0f5fe7..581840c 100644
--- a/examples/tutorial15.rs
+++ b/examples/tutorial15.rs
@@ -10,7 +10,7 @@ pub mod mycrate {
 
     derive_str_cherr!(Func2Error);
 
-    fn func2() -> std::result::Result<(), Box<std::error::Error + Send + Sync>> {
+    fn func2() -> std::result::Result<(), Box<dyn std::error::Error + Send + Sync>> {
         let filename = "foo.txt";
         do_some_io(filename)
             .map_err(|e| cherr!(e, Func2Error(format!("Error reading '{}'", filename))))?;
@@ -52,7 +52,7 @@ pub mod mycrate {
     }
 
     impl From<&(dyn std::error::Error + 'static + Send + Sync)> for ErrorKind {
-        fn from(e: &(dyn std::error::Error + 'static  + Send + Sync)) -> Self {
+        fn from(e: &(dyn std::error::Error + 'static + Send + Sync)) -> Self {
             if let Some(_) = e.downcast_ref::<io::Error>() {
                 ErrorKind::IO(String::from("Unknown filename"))
             } else if let Some(_) = e.downcast_inner_ref::<Func2Error>() {
@@ -63,8 +63,8 @@ pub mod mycrate {
         }
     }
 
-    impl From<&std::boxed::Box<dyn std::error::Error + 'static  + Send + Sync>> for ErrorKind {
-        fn from(e: &std::boxed::Box<dyn std::error::Error + 'static  + Send + Sync>) -> Self {
+    impl From<&std::boxed::Box<dyn std::error::Error + 'static + Send + Sync>> for ErrorKind {
+        fn from(e: &std::boxed::Box<dyn std::error::Error + 'static + Send + Sync>) -> Self {
             Self::from(&**e)
         }
     }
@@ -99,10 +99,9 @@ pub mod mycrate {
         func1().map_err(minto_cherr!(ErrorKind))?;
         Ok(())
     }
-
 }
 
-fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
     use mycrate::super_func1;
     use mycrate::ErrorKind;
     use std::error::Error;
@@ -119,7 +118,7 @@ fn main() -> Result<(), Box<std::error::Error + Send + Sync>> {
         }
 
         eprintln!();
-        let mut s: &Error = &e;
+        let mut s: &dyn Error = &e;
         while let Some(c) = s.source() {
             if let Some(ioerror) = c.downcast_ref::<io::Error>() {
                 eprintln!("caused by: std::io::Error: {}", ioerror);
diff --git a/examples/tutorial2.rs b/examples/tutorial2.rs
index 349c5cd..b13f0cc 100644
--- a/examples/tutorial2.rs
+++ b/examples/tutorial2.rs
@@ -4,25 +4,25 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = do_some_io() {
         Err(cherr!(e, "func2 error"))?;
     }
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func2() {
         Err(cherr!(e, "func1 error"))?;
     }
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     func1()
 }
diff --git a/examples/tutorial3.rs b/examples/tutorial3.rs
index cdbffed..6da067c 100644
--- a/examples/tutorial3.rs
+++ b/examples/tutorial3.rs
@@ -4,22 +4,22 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     do_some_io().map_err(|e| cherr!(e, "func2 error"))?;
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(|e| cherr!(e, "func1 error"))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         eprintln!("{:?}", e);
     }
diff --git a/examples/tutorial4.rs b/examples/tutorial4.rs
index d037215..e1225c0 100644
--- a/examples/tutorial4.rs
+++ b/examples/tutorial4.rs
@@ -3,23 +3,23 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(mstrerr!("func1 error"))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         eprintln!("{:?}", e);
     }
diff --git a/examples/tutorial5.rs b/examples/tutorial5.rs
index 4d673e3..cb80569 100644
--- a/examples/tutorial5.rs
+++ b/examples/tutorial5.rs
@@ -3,18 +3,18 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func2() {
         if let Some(s) = e.source() {
             eprintln!("func2 failed because of '{}'", s);
@@ -24,7 +24,7 @@ fn func1() -> Result<(), Box<Error + Send + Sync>> {
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         eprintln!("{}", e);
     }
diff --git a/examples/tutorial6.rs b/examples/tutorial6.rs
index 22e0e78..996540c 100644
--- a/examples/tutorial6.rs
+++ b/examples/tutorial6.rs
@@ -3,26 +3,26 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(mstrerr!("func1 error"))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         eprintln!("Error: {}", e);
-        let mut s : &(dyn Error) = e.as_ref();
+        let mut s: &(dyn Error) = e.as_ref();
         while let Some(c) = s.source() {
             if let Some(ioerror) = c.downcast_ref::<io::Error>() {
                 eprintln!("caused by: std::io::Error: {}", ioerror);
diff --git a/examples/tutorial7.rs b/examples/tutorial7.rs
index bf09449..b36fa8b 100644
--- a/examples/tutorial7.rs
+++ b/examples/tutorial7.rs
@@ -3,23 +3,23 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
     Ok(())
 }
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(mstrerr!("func1 error"))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         eprintln!("Error: {}", e);
         if let Some(s) = e.downcast_chain_ref::<String>() {
diff --git a/examples/tutorial8.rs b/examples/tutorial8.rs
index be92df7..1644a32 100644
--- a/examples/tutorial8.rs
+++ b/examples/tutorial8.rs
@@ -3,14 +3,14 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
 derive_str_cherr!(Func2Error);
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     Ok(())
@@ -18,12 +18,12 @@ fn func2() -> Result<(), Box<Error + Send + Sync>> {
 
 derive_str_cherr!(Func1Error);
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         if let Some(f1err) = e.downcast_chain_ref::<Func1Error>() {
             eprintln!("Func1Error: {}", f1err);
diff --git a/examples/tutorial9.rs b/examples/tutorial9.rs
index d9436f4..99b0f23 100644
--- a/examples/tutorial9.rs
+++ b/examples/tutorial9.rs
@@ -3,14 +3,14 @@ use std::error::Error;
 use std::io;
 use std::result::Result;
 
-fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     Err(io::Error::from(io::ErrorKind::NotFound))?;
     Ok(())
 }
 
 derive_str_cherr!(Func2Error);
 
-fn func2() -> Result<(), Box<Error + Send + Sync>> {
+fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     let filename = "foo.txt";
     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     Ok(())
@@ -19,14 +19,14 @@ fn func2() -> Result<(), Box<Error + Send + Sync>> {
 derive_str_cherr!(Func1ErrorFunc2);
 derive_str_cherr!(Func1ErrorIO);
 
-fn func1() -> Result<(), Box<Error + Send + Sync>> {
+fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     func2().map_err(mstrerr!(Func1ErrorFunc2, "func1 error calling func2"))?;
     let filename = "bar.txt";
     do_some_io().map_err(mstrerr!(Func1ErrorIO, "Error reading '{}'", filename))?;
     Ok(())
 }
 
-fn main() -> Result<(), Box<Error + Send + Sync>> {
+fn main() -> Result<(), Box<dyn Error + Send + Sync>> {
     if let Err(e) = func1() {
         if let Some(s) = e.downcast_ref::<ChainError<Func1ErrorIO>>() {
             eprintln!("Func1ErrorIO:\n{:?}", s);
diff --git a/src/lib.rs b/src/lib.rs
index f378585..d68a1b6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -32,18 +32,18 @@
 //! use std::io;
 //! use std::result::Result;
 //!
-//! fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+//! fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
 //!     Err(io::Error::from(io::ErrorKind::NotFound))?;
 //!     Ok(())
 //! }
 //!
-//! fn func2() -> Result<(), Box<Error + Send + Sync>> {
+//! fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
 //!     let filename = "foo.txt";
 //!     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
 //!     Ok(())
 //! }
 //!
-//! fn func1() -> Result<(), Box<Error + Send + Sync>> {
+//! fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
 //!     func2().map_err(mstrerr!("func1 error"))?;
 //!     Ok(())
 //! }
@@ -74,12 +74,12 @@
 //! use std::io;
 //! use std::result::Result;
 //!
-//! fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+//! fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
 //!     Err(io::Error::from(io::ErrorKind::NotFound))?;
 //!     Ok(())
 //! }
 //!
-//! fn func3() -> Result<(), Box<Error + Send + Sync>> {
+//! fn func3() -> Result<(), Box<dyn Error + Send + Sync>> {
 //!     let filename = "foo.txt";
 //!     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
 //!     Ok(())
@@ -246,14 +246,14 @@ impl<T: 'static + Display + Debug> ChainError<T> {
     /// use std::error::Error;
     /// use std::io;
     ///
-    /// fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+    /// fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     ///     Err(io::Error::from(io::ErrorKind::NotFound))?;
     ///     Ok(())
     /// }
     ///
     /// derive_str_cherr!(Func2Error);
     ///
-    /// fn func2() -> Result<(), Box<Error + Send + Sync>> {
+    /// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     ///     let filename = "foo.txt";
     ///     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     ///     Ok(())
@@ -261,7 +261,7 @@ impl<T: 'static + Display + Debug> ChainError<T> {
     ///
     /// derive_str_cherr!(Func1Error);
     ///
-    /// fn func1() -> Result<(), Box<Error + Send + Sync>> {
+    /// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
     ///     func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
     ///     Ok(())
     /// }
@@ -351,14 +351,14 @@ impl<T: 'static + Display + Debug> ChainError<T> {
     /// use std::error::Error;
     /// use std::io;
     ///
-    /// fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+    /// fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
     ///     Err(io::Error::from(io::ErrorKind::NotFound))?;
     ///     Ok(())
     /// }
     ///
     /// derive_str_cherr!(Func2Error);
     ///
-    /// fn func2() -> Result<(), Box<Error + Send + Sync>> {
+    /// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
     ///     let filename = "foo.txt";
     ///     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
     ///     Ok(())
@@ -801,7 +801,7 @@ macro_rules! minto_cherr {
 /// #         }
 /// #     }
 /// # }
-/// fn do_some_stuff() -> Result<(), Box<Error + Send + Sync>> {
+/// fn do_some_stuff() -> Result<(), Box<dyn Error + Send + Sync>> {
 ///     Err(io::Error::from(io::ErrorKind::NotFound))?;
 ///     Ok(())
 /// }
@@ -850,17 +850,17 @@ macro_rules! cherr {
 /// # use std::error::Error;
 /// # use std::io;
 /// # use std::result::Result;
-/// # fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
 /// #     Err(io::Error::from(io::ErrorKind::NotFound))?;
 /// #     Ok(())
 /// # }
-/// fn func2() -> Result<(), Box<Error + Send + Sync>> {
+/// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
 ///     let filename = "foo.txt";
 ///     do_some_io().map_err(mstrerr!("Error reading '{}'", filename))?;
 ///     Ok(())
 /// }
 ///
-/// fn func1() -> Result<(), Box<Error + Send + Sync>> {
+/// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
 ///     func2().map_err(mstrerr!("func1 error"))?;
 ///     Ok(())
 /// }
@@ -891,13 +891,13 @@ macro_rules! cherr {
 /// # use std::error::Error;
 /// # use std::io;
 /// # use std::result::Result;
-/// # fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
 /// #     Err(io::Error::from(io::ErrorKind::NotFound))?;
 /// #     Ok(())
 /// # }
 /// derive_str_cherr!(Func2Error);
 ///
-/// fn func2() -> Result<(), Box<Error + Send + Sync>> {
+/// fn func2() -> Result<(), Box<dyn Error + Send + Sync>> {
 ///     let filename = "foo.txt";
 ///     do_some_io().map_err(mstrerr!(Func2Error, "Error reading '{}'", filename))?;
 ///     Ok(())
@@ -905,7 +905,7 @@ macro_rules! cherr {
 ///
 /// derive_str_cherr!(Func1Error);
 ///
-/// fn func1() -> Result<(), Box<Error + Send + Sync>> {
+/// fn func1() -> Result<(), Box<dyn Error + Send + Sync>> {
 ///     func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
 ///     Ok(())
 /// }
@@ -961,7 +961,7 @@ macro_rules! mstrerr {
 ///
 /// derive_str_cherr!(Func1Error);
 ///
-/// fn func1() -> Result<(), Box<Error>> {
+/// fn func1() -> Result<(), Box<dyn Error>> {
 ///     func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
 ///     Ok(())
 /// }
@@ -1009,7 +1009,7 @@ macro_rules! strerr {
 /// # use std::error::Error;
 /// # use std::io;
 /// # use std::result::Result;
-/// # fn do_some_io() -> Result<(), Box<Error + Send + Sync>> {
+/// # fn do_some_io() -> Result<(), Box<dyn Error + Send + Sync>> {
 /// #     Err(io::Error::from(io::ErrorKind::NotFound))?;
 /// #     Ok(())
 /// # }
@@ -1023,7 +1023,7 @@ macro_rules! strerr {
 ///
 /// derive_str_cherr!(Func1Error);
 ///
-/// fn func1() -> Result<(), Box<Error>> {
+/// fn func1() -> Result<(), Box<dyn Error>> {
 ///     func2().map_err(mstrerr!(Func1Error, "func1 error"))?;
 ///     Ok(())
 /// }
diff --git a/tests/test_iter.rs b/tests/test_iter.rs
index c451f7f..488ed0b 100644
--- a/tests/test_iter.rs
+++ b/tests/test_iter.rs
@@ -4,7 +4,7 @@ use std::fmt::Write;
 use std::io;
 
 #[test]
-fn test_iter() -> Result<(), Box<Error + Send + Sync>> {
+fn test_iter() -> Result<(), Box<dyn Error + Send + Sync>> {
     let err = io::Error::from(io::ErrorKind::NotFound);
     let err = cherr!(err, "1");
     let err = cherr!(err, "2");
@@ -31,7 +31,7 @@ fn test_iter() -> Result<(), Box<Error + Send + Sync>> {
 }
 
 #[test]
-fn test_find_cause() -> Result<(), Box<Error + Send + Sync>> {
+fn test_find_cause() -> Result<(), Box<dyn Error + Send + Sync>> {
     let err = io::Error::from(io::ErrorKind::NotFound);
     let err = cherr!(err, "1");
     let err = cherr!(err, "2");
@@ -48,7 +48,7 @@ fn test_find_cause() -> Result<(), Box<Error + Send + Sync>> {
 }
 
 #[test]
-fn test_root_cause() -> Result<(), Box<Error + Send + Sync>> {
+fn test_root_cause() -> Result<(), Box<dyn Error + Send + Sync>> {
     let err = io::Error::from(io::ErrorKind::NotFound);
     let err = cherr!(err, "1");
     let err = cherr!(err, "2");